Continuing or stopping 5‐aminosalicylates in patients with inflammatory bowel disease on anti‐TNF therapy: A nationwide population‐based study

Summary Background The impact of continuing or stopping 5‐aminosalicylates (5‐ASA) after commencing anti‐tumour necrosis factor (anti‐TNF) therapy in patients with inflammatory bowel disease (IBD) remains unclear. Aims To compare the outcomes of patients with IBD who stopped or continued 5‐ASA after starting anti‐TNF therapy. Methods We analysed data from the Korean National Health Insurance claims database between 2007 and 2020. We compared the clinical outcomes of patients who stopped or continued 5‐ASA within 90 days of anti‐TNF initiation. The primary outcome was any adverse clinical event defined as a composite of new corticosteroid use, IBD‐related hospitalisation, or intestinal surgery. Results Among 7442 patients included for analysis (4479 [60.2%] with Crohn's disease [CD] and 2963 [39.8%] with ulcerative colitis [UC]), 1037 (13.9%) discontinued 5‐ASA within 90 days of starting anti‐TNF therapy. During a median 4.3‐year follow‐up, discontinuation of 5‐ASA was not associated with an increased risk of adverse clinical events (adjusted hazard ratio 1.01, 95% confidence interval 0.93–1.10). The cumulative incidence of each adverse clinical event and the composite outcome were not significantly different between groups (all, p > 0.05). Additionally, separate analyses in CD and UC cohorts revealed no differences in adverse clinical outcomes between the 5‐ASA continuation and discontinuation groups. Subgroup analyses by presumed risk factors for disease relapse showed no significant differences in the risk of adverse events between groups. Conclusions In this nationwide population‐based study, discontinuing 5‐ASA after starting anti‐TNF therapy was not associated with an increased risk of adverse events in patients with IBD.